Radial piston pump for pumping water

ABSTRACT

The radial piston pump for pumping water, especially pure water, comprises pump housing, a central drive mechanism and a surrounding pump mechanism which has a plurality of piston-and-cylinder units radially oriented and distributed about its circumference. Inlet and outlet valves for individual cylinder chambers are located in the vicinity of the piston-and-cylinder units. The drive mechanism is located in a housing chamber which has an oil sump. The housing chamber is surrounded by a cooling device comprising a plurality of gaps and ducts for conducting water to the inlet valves which are provided with a suction intake fitting for admitting water.

FIELD OF THE INVENTION

Our present invention relates to a radial piston pump for pumping water,especially pure or clean water.

BACKGROUND OF THE INVENTION

A radial piston pump for pumping water generally comprises a pumphousing, a central drive mechanism and a surrounding pumping mechanismwhich has a plurality of radially oriented piston-and-cylinder unitsdistributed around its circumference. The inlet and outlet valves forthe individual cylinder chambers are positioned in the vicinity of thepiston-and-cylinder units. Particularly these pumps are high pressurepumps. "Pure water" here means water without added lubricating agents.

In the conventional radial piston pump of the described type and for thedescribed purpose, the drive mechanism runs in the water to be pumped orfed. That has proven satisfactory when the water to be pumped contains alubricant in sufficient quantities, e.g. a lubricant/water emulsioncontaining water with about 5% lubricant.

With decreasing lubricant content of the water to be pumped oneobserves, especially at higher pumping speeds, increasing heatgeneration and a troublesome heating of the drive mechanism and theentire pump housing. The water containing the lubricant is anenvironmental contaminant when disposed of after use.

OBJECTS OF THE INVENTION

It is an object of our invention to provide an improved radial pistonpump for pumping water which is free from the above mentioneddisadvantages or difficulties.

It is another object of our invention to provide an improved radialpiston pump for pumping water in which detrimental heating of the drivemechanism and housing cannot occur, even when pure water is beingpumped.

SUMMARY OF THE INVENTION

These objects and others which will become more readily apparenthereinafter attained, in accordance with our invention, in a radialpiston pump water, especially pure water, comprising a pump housing, acentral drive mechanism and a surrounding pump mechanism which has aplurality of radially oriented piston-and-cylinder units distributedover its circumference. The inlet and outlet valves of the individualcylinder chambers are located in the vicinity of the piston-and-cylinderunits.

According to our invention the drive mechanism is located in a housingchamber which has an oil sump or pan and the housing chamber issurrounded by a cooling device comprising a plurality of gaps and ductsfor conducting the water to the inlet valves.

These gaps and ducts are connected with a suction intake fitting for thepumped water, e.g. a fitting provided with a foot valve or suctionvalve.

The housing chamber for the drive mechanism is constructed as a closedchamber except for a filling and emptying port. The cooling isparticularly intensive when the gaps are located on both sides of thehousing chamber for the drive mechanism and the ducts are arrayed tosurround the housing chamber, passing axially parallel to one anotherbetween the gaps on opposite axial sides of the housing chamber. Theducts can be formed as passages. The housing chamber has at least onechamber-forming wall with at least one cooling rib directed into thegaps for promoting heat transfer from the oil to the water drawn inthrough the fitting and passing to the intake vales.

Hence, the water pumped simultaneously can fulfill an additionalfunction, namely a cooling function for the drive mechanism.

The drive mechanism itself runs in a lubricant and develops little heat.

The cooling provided by our invention is thus sufficient for alloperating conditions of the radial piston pump and is intensive with ahigh volume flow of the water to be pumped and thus with higher pumpingrates. It is not necessary to add a lubricant to the water pumped as hasbeen done heretofore.

The radial piston pump is particularly suitable for pumping pure(lubricant-free) water and also extremely pure water. During operationof the conventional radial piston pump, when heat generation occurs, thelubricant is circulated through a separate cooling device. Such acooling device is not necessary in the radial piston pump according toour invention.

BRIEF DESCRIPTION OF THE DRAWING

The above and other objects, features and advantages of our inventionwill become more readily apparent from the following description,reference being made to the accompanying highly diagrammatic drawing inwhich:

FIG. 1 is an axial cross sectional view of one embodiment of a radialpiston pump for water according to our invention;

FIG. 2 is a cross sectional view taken along the section line II--II ofFIG. 1; and

FIG. 3 is a view similar to FIG. 2 through another embodiment of aradial piston pump according to our invention.

SPECIFIC DESCRIPTION

The radial piston pump shown in the drawing basically comprises a pumphousing 1, a central drive mechanism 2 and a surrounding pump mechanism3. A drive shaft 4 to which a drive in the form of a motor/gear unit isconnected is part of the central drive mechanism 2. The drive can belocated on the left side of FIG. 1.

The pump mechanism 3 has a plurality of piston-and-cylinder units 5distributed around the circumference of the pump (FIG. 3). In thevicinity of the piston-and-cylinder units 5 the inlet and outlet valves6 and/or 7 for the pumped water are located. These vales are positionedto communicate with the respective pumping cylinders at opposite axialsides of the housing provided with the pumping cylinders.

The drive mechanism 2 is mounted in a housing chamber 8 whosechamber-forming walls 9 are indicated in FIG. 1 by closely spacedsectional hatching. This housing chamber 8 has an oil sump 10.

The design is such that the housing chamber 8 is surrounded by a coolingdevice which comprises a plurality of taps 11 between front and rearaxially spaced end walls of the chamber 8 and walls of the pump housingspacedly flanking same, and ducts 12 (which extend parallel to the axis,surround the chamber 8 and connect the gaps 11) for conducting thepumped water to the inlet valves 6 (which communicate with one of thegaps 11). The gaps and passages 11, 12 are provided with a suitablesuction intake fitting 13 for the water which is located as centrally aspossible. The housing chamber 8 for the drive mechanism 2 in thisembodiment is advantageously formed as a closed chamber except for afilling and emptying port 14 for the lubricating medium. The gaps 11 arelocated on both sides of the housing chamber 8 for the drive mechanism2. The ducts 12 are distributed over the circumference or periphery inthe valve body surrounding chamber 8 and located substantially parallelto the drive shaft 4. They are formed as passages. The ducts 12 extendfrom the distributor chamber 15 at one gap 11 open into the collectorchamber at the other gap 11 and at which the pump cylinders communicatevia the intake fittings 13.

From FIG. 1 it will be apparent that it is possible to provide thechamber-forming walls 9 of the housing chamber 8 with cooling ribs 18directed into the gaps 11.

In the embodiment shown in FIG. 3 a plurality of inlet valves 6 areindicated corresponding to the plurality of piston-and-cylinder units 5in the main embodiment presented here. In the embodiment shown in FIG. 2which is similar, only one inlet valve 6 is shown corresponding to asingle piston-cylinder device 5. The embodiment of FIG. 3 has the samestructure as indicated in FIG. 1 except that there are a plurality ofpiston-and-cylinder units 5 correspondingly distributedcircumferentially.

We claim:
 1. A radial piston pump for pumping water, comprising:meansforming a closed chamber having a single fitting enabling theintroduction of a lubricant into and draining of the lubricant from saidchamber, said chamber having a pair of axially spaced end walls; a pumpbody peripherally surrounding said chamber and formed with at least oneradially oriented piston-and-cylinder pumping unit having an intakevalve at one axial side of said body and an outlet valve at an oppositeaxial side of said body; a pump housing having axially spaced end wallsjuxtaposed with said end walls of said chamber and said sides of saidbody, said end walls of said housing defining with said end walls ofsaid chamber a pair of axially spaced gaps with one of said gapscommunicating with said intake valve, said body being formed with aplurality of passages parallel to an axis of said chamber, communicatingbetween said gaps and arrayed around said chamber, said housing beingformed with a suction intake fitting communicating with said gaps andsaid passages for delivering water to said intake valve, whereby saidwater passes in heat exchanging relationship with said lubricant throughsaid end walls and said periphery of said chamber; and a drive mechanismfor said unit having a shaft extending axially into said chamber andprovided within said chamber with means immersed in said lubricant foractuating said unit.
 2. The radial piston pump defined in claim 1wherein said end walls of said chamber are provided with heat-exchangepromoting ribs formed on said end walls of said chamber and projectinginto said gaps.
 3. The radial piston pump defined in claim 2 whereinsaid valve body is formed with a plurality of said piston-and-cylinderpumping units each having an intake valve at said one axial side of saidbody and an outlet valve at said opposite axial side of said body, allof said units being driven by said drive mechanism, all of said intakevalves communicating with said one of said gaps.